gen/nftw.c

   1 /*      $OpenBSD: nftw.c,v 1.2 2003/07/21 21:15:32 millert Exp $        */
   2
   3 /*
   4  * Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  * Sponsored in part by the Defense Advanced Research Projects
  19  * Agency (DARPA) and Air Force Research Laboratory, Air Force
  20  * Materiel Command, USAF, under agreement number F39502-99-1-0512.
  21  */
  22
  23 #if defined(LIBC_SCCS) && !defined(lint)
  24 static const char rcsid[] = "$OpenBSD: nftw.c,v 1.2 2003/07/21 21:15:32 millert Exp $";
  25 #endif /* LIBC_SCCS and not lint */
  26
  27 #include <stdio.h>
  28 #include <sys/cdefs.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <errno.h>
  32 #include <fts.h>
  33 #include <ftw.h>
  34 #include <limits.h>
  35 #include <fcntl.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38
  39 static int
  40 both_ftw(const char *path,
  41         int (*ofn)(const char *, const struct stat *, int),
  42         int (*nfn)(const char *, const struct stat *, int, struct FTW *),
  43         int nfds, int ftwflags)
  44 {
  45         const char *paths[2];
  46         struct FTW ftw;
  47         FTSENT *cur;
  48         FTS *ftsp;
  49         int ftsflags, fnflag, error, postorder, sverrno;
  50         int cwd_fd = -1; /* cwd_fd != -1 means call chdir a lot */
  51
  52 #if __DARWIN_UNIX03
  53         /* Macro to skip the mount point itself in UNiX03 mode, in legcy
  54           mode the mount point is returned, but we don't decend into it */
  55 #define SKIP_MOUNT if ((ftwflags & FTW_MOUNT) \
  56       && cur->fts_statp->st_dev != path_stat.st_dev) { \
  57         continue; \
  58     }
  59 #else
  60 #define SKIP_MOUNT
  61 #endif
  62
  63         /* XXX - nfds is currently unused */
  64         if (nfds < 1 || nfds > OPEN_MAX) {
  65                 errno = EINVAL;
  66                 return (-1);
  67         }
  68
  69         ftsflags = FTS_COMFOLLOW;
  70         if (!(ftwflags & FTW_CHDIR))
  71                 ftsflags |= FTS_NOCHDIR;
  72         if (ftwflags & FTW_MOUNT)
  73                 ftsflags |= FTS_XDEV;
  74         if (ftwflags & FTW_PHYS) {
  75                 ftsflags |= FTS_PHYSICAL;
  76         } else {
  77                 ftsflags |= FTS_LOGICAL;
  78         }
  79         postorder = (ftwflags & FTW_DEPTH) != 0;
  80
  81         /* We have been requested to change directories, and fts doesn't
  82           always do it (never for FTS_LOGICAL, and sometimes not for
  83           FTS_PHYSICAL) */
  84         if (ftwflags & FTW_CHDIR) {
  85             cwd_fd = open(".", O_RDONLY, 0);
  86             if (cwd_fd < 0) {
  87                 return -1;
  88             }
  89             /* Prevent problems if fts ever starts using chdir when passed
  90               FTS_PHYSICAL */
  91             ftsflags |= FTS_NOCHDIR;
  92         }
  93
  94 #if __DARWIN_UNIX03
  95         struct stat path_stat;
  96
  97         /* UNIX03 requires us to return -1/errno=ELOOP if path
  98           is a looping symlink; fts_open is succesful and fts_read
  99           gives us FTS_NS which isn't very useful, in fact we get
 100           pretty much the same behaviour for ENAMETOOLONG, ENOENT,
 101           ENOTDIR, and EACCES */
 102         {
 103             int rc = stat(path, &path_stat);
 104             int e = errno;
 105             if (rc < 0
 106               && (errno == ELOOP || errno == ENAMETOOLONG || errno == ENOENT
 107               || errno == ENOTDIR || errno == EACCES)) {
 108                     return -1;
 109             }
 110             if (rc >= 0 && nfn) {
 111                 if (!S_ISDIR(path_stat.st_mode)) {
 112                     errno = ENOTDIR;
 113                     return -1;
 114                 }
 115             }
 116         }
 117 #endif
 118         paths[0] = path;
 119         paths[1] = NULL;
 120         ftsp = fts_open((char * const *)paths, ftsflags, NULL);
 121         if (ftsp == NULL) {
 122             return (-1);
 123         }
 124         error = 0;
 125         while ((cur = fts_read(ftsp)) != NULL) {
 126                 switch (cur->fts_info) {
 127                 case FTS_D:
 128                         if (postorder)
 129                                 continue;
 130                         SKIP_MOUNT;
 131                         /* we will get FTS_DNR next (this is not an issue for
 132                           FTS_DP, only FTS_D) */
 133                         if (access(cur->fts_path, R_OK) != 0)
 134                             continue;
 135                         fnflag = FTW_D;
 136                         break;
 137                 case FTS_DNR:
 138                         fnflag = FTW_DNR;
 139                         break;
 140                 case FTS_DP:
 141                         if (!postorder)
 142                                 continue;
 143                         SKIP_MOUNT;
 144                         fnflag = FTW_DP;
 145                         break;
 146                 case FTS_F:
 147                 case FTS_DEFAULT:
 148                         fnflag = FTW_F;
 149                         break;
 150                 case FTS_NS:
 151                 case FTS_NSOK:
 152                         fnflag = FTW_NS;
 153                         break;
 154                 case FTS_SL:
 155                         fnflag = FTW_SL;
 156                         break;
 157                 case FTS_SLNONE:
 158                         fnflag = nfn ? FTW_SLN : FTW_SL;
 159 #if __DARWIN_UNIX03
 160                         {
 161                             /* The legacy behaviour did not signal an error
 162                               on symlink loops unless they ended up causing
 163                               a directory cycle, but the Unix2003 standard
 164                               requires ELOOP to end ftw and nftw walks with
 165                               an error */
 166                             struct stat sb;
 167                             int rc = stat(cur->fts_path, &sb);
 168                             if (rc < 0 && errno == ELOOP) {
 169                                 error = -1;
 170                                 goto done;
 171                             }
 172                         }
 173 #endif
 174                         break;
 175                 case FTS_DC:
 176 #if __DARWIN_UNIX03
 177                         /* Unix03 says nftw should break cycles and not return
 178                           errors in physical mode (which is definitly what it
 179                           says ftw can't do) */
 180                         if (nfn && !(ftwflags & FTW_PHYS)) {
 181                                 fnflag = FTW_D;
 182                                 break;
 183                         }
 184 #endif
 185                         errno = ELOOP;
 186                         /* FALLTHROUGH */
 187                 default:
 188                         error = -1;
 189                         goto done;
 190                 }
 191
 192                 if (cwd_fd >= 0) {
 193                     char *dir, *free_me = NULL;
 194                     if (fnflag == FTW_D) {
 195                         dir = cur->fts_path;
 196                     } else {
 197                         /* we could alloc just enough for the directory,
 198                           and use memmove -- but that is a little more
 199                           error prone, and not noticable in with all the
 200                           extra work... */
 201                         dir = free_me = strdup(cur->fts_path);
 202                         dir[cur->fts_pathlen - cur->fts_namelen] = '\0';
 203                     }
 204                     int rc = chdir(dir);
 205                     if (free_me) {
 206                         free(free_me);
 207                     }
 208                     if (rc < 0) {
 209                         error = -1;
 210                         goto done;
 211                     }
 212                 }
 213                 if (nfn) {
 214                     ftw.base = cur->fts_pathlen - cur->fts_namelen;
 215                     ftw.level = cur->fts_level;
 216                     error = nfn(cur->fts_path, cur->fts_statp, fnflag, &ftw);
 217                 } else {
 218                     error = ofn(cur->fts_path, cur->fts_statp, fnflag);
 219                 }
 220                 if (cwd_fd >= 0) {
 221                     if (fchdir(cwd_fd) < 0) {
 222                         error = -1;
 223                         goto done;
 224                     }
 225                 }
 226
 227                 if (error != 0)
 228                         break;
 229         }
 230 done:
 231         sverrno = errno;
 232         (void) fts_close(ftsp);
 233         errno = sverrno;
 234         return (error);
 235 }
 236
 237 int
 238 ftw(const char *path, int (*fn)(const char *, const struct stat *, int),
 239     int nfds)
 240 {
 241         /* The legacy implmentation didn't follow symlinks, but Unix03
 242           does - this was likely a bug in the legacy implemtation; JKH
 243           thinks we ought change the legacy behaviour, and I agree; anyone
 244           who doesn't should replace FTW_PHYS with
 245           __DARWIN_UNIX03 ? 0 : FTW_PHYS */
 246         return both_ftw(path, fn, NULL, nfds, FTW_PHYS);
 247 }
 248
 249 int
 250 nftw(const char *path, int (*fn)(const char *, const struct stat *, int,
 251      struct FTW *), int nfds, int ftwflags)
 252 {
 253         return both_ftw(path, NULL, fn, nfds, ftwflags);
 254 }